DOI: https://doi.org/10.30970/jps.01.267
THE APICAL OXYGEN INFLUENCE ON CRITICAL TEMPERATURE OF Hg–BASED SUPERCONDUCTING CUPRATES
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Journal of Physical Studies 1(2), 267–272 (1997)
DOI: https://doi.org/10.30970/jps.01.267 THE APICAL OXYGEN INFLUENCE ON CRITICAL TEMPERATURE OF Hg–BASED SUPERCONDUCTING CUPRATES |
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Yu. N. Myasoedov, R. V. Lutciv, A. B. Skira
Ivan Franko Lviv State University, Chair of Semiconductor Physics
50 Dragomanov Str., Lviv UA-290005, Ukraine
The analysis of changes in critical temperature ($T_c$) as a function of structural parameters is performed for the Hg–based superconductors. We found that there exists a correlation between $T_c$ and Madelung potential difference ($Δ V$) for holes ($p$) at apical oxygen ($O_A$) and oxygen ($O_p$) sites in the (CuO$_2$) plane. A change of the Madelung potential of holes for the varying occupancy factor of oxygen in the Hg–plane was calculated. We showed that a parabolical dependence of $T_c(p)$ for Hg–1201 is trasformed to a ‟boomerang" like dependence for Hg–1223.
The Madelung potential difference $Δ V_{a-p}^{opt}$ ($Δ V_{a-p}= Δ V_{a-p}^{opt}$ at $n=n^{opt}$) increases from 7.44 eV to 9.86 eV for Hg–HTSC compounds with the (CuO$_2$) layer per unit cell from $n=1$ to 3, respectively. The change of $Δ V_{a-p}$ is a result of the crystal structure local distortions. The main conclusion of this work is a considerable influence of ions local geometry near the (CuO$_2$) layer on superconducting properties.